The CertVerifierJob destructor should delete canceled requests.
Add a job to inflight_ only after the job's worker has started
successfully.
R=agl
BUG=63357, 67289
TEST=net_unittests --gtest_filter=CertVerifierTest.CancelRequestThenQuit
should not leak a CertVerifierRequest object under valgrind.
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=72203

agl: your dnsrr_resolver.cc code doesn't have this memory
leak because the RRResolverJob destructor calls PostAll().
I didn't copy that code because I don't want the callbacks
to run when CertVerifier is deleted, but the problem is
that properly canceled requests are leaked. (Post() not
only calls the callback, if not canceled, but also delete
itself.)
The inflight_ change was suggested by willchan in his
code review for CertVerifier.